Numerous types of mechanical, or electromechanical, or electronic or digital equipment, approved by the Postal Authorities, are currently known and available in commerce for the apposition of prints and/or stamps proving that the amount due for postage has been paid.
As everyone knows, this equipment, usually called franking machines, has been a great commercial success due to its ability to satisfy requirements of both security and practicality, in connection with the franking operations of large volume postal shipments.
In general, the systems automatically generating postage stamps are widely known and have been in application for some time, particularly ever since Arthur H. Pitney invented the first franking machine, corresponding to U.S. Pat. No. 1,530,852 of 24 Mar. 1925.
In the current state of the art, postal franking systems have become highly automated systems in which manual intervention has been reduced to the minimum.
Over the years, though there have been countless changes in the shape and structure of franking machines, one requirement has remained essentially unchanged and has constantly guided research, that of endowing postal systems with an ever greater degree of security against the risk of fraud.
It is essential in fact that, when the franking machine prints a stamp or a postal impression, it operates under conditions of absolute security, in order to avoid or at least minimize the risk of printing unauthorized stamps, and the consequent risk of seriously damaging the Postal Authority.
In the past, the main security measures implemented on franking machines were of a physical nature. For example, in mechanical franking machines, safety elements were applied to both the printing devices and the calculating devices. More recently, systems have been introduced that are based on the use of encryption techniques to ensure the validity of digitally printed postage stamps.
However the safety systems used or proposed have only reduced the risk associated with an unauthorized printing of postage stamps, and have not eliminated it entirely. This risk is borne entirely by the Postal Authority in both the case of stamps printed using pre-paid cards and in cases where remote payment systems are used.
Then there are other systems known from patents U.S. Pat. Nos. 5,111,030, 5,539,190, 5,917,924, 6,199,752, for the emission of franking marks and typically postage stamps, that involve the use of one or more smart cards, in order to ensure greater security in managing the data and equipment employed for generating postage stamps.
In particular, these solutions have in common the possibility of using a plurality of smart cards on the same franking machine, thereby permitting various users to make use of the franking machine.
Unfortunately however these solutions have the disadvantage of being somewhat complex and also not very versatile for producing a distributed official stamp issuing system.
To return to the current context, the franking market requires more direct and effective solutions for issuing at the places of use not only the stamp product, but also similar objects, such as for instance revenue stamps, and also solutions capable of allowing timely checking of the market trend by the service operator (Postal Authority).
In general, the solutions to these market requirements must satisfy various criteria, such as:                elasticity of the service;                    reduction to the absolute minimum of the amount of cash tied up by the user or retailer, needed to be able to manage the issuing of official stamps;                        optimisation of the variety of sizes and denominations available so as to satisfy the user needs and/or the requirements of customers;        variability of the graphic mark of the impression depending on the needs of the postal service operator; and        possibility of customising the content of the impression, or at least a part of it, to allow it to convey advertising messages.        